Polymer nanocomposites polymeric materials

Lii, C. L., Cheng, Y. R., Liu, Y. R, Liu, R, and Yang, B. 2006. A facile route to ZnS-polymer nanocomposite optical materials with high nanophase content via y-ray irradiation initiated bulk polymerization. Adv. Mater. 18 1188-1192. 

The quantity of the hterature in the field of the nanocomposite polymeric materials has grown multiple times in recent years. The possibility to use almost all polymeric and polycondensated materials as a matrix is shown The nanocomposites from various organoclays and polymers have been synthesized. Here is just a small part of the compounds for being the matrix referenced in literature polyacrylate [83], polyamides [82,84,85], polybenzoxazine [86], polybutylene terephtalate [11,82,87], polyimides [88], polycarbonate [89], polymethylmetaciylate [90], polypropylene [91,92], poly-... 

Recent demands for polymeric materials request them to be multifunctional and high performance. Therefore, the research and development of composite materials have become more important because single-polymeric materials can never satisfy such requests. Especially, nanocomposite materials where nanoscale fillers are incorporated with polymeric materials draw much more attention, which accelerates the development of evaluation techniques that have nanometer-scale resolution." To date, transmission electron microscopy (TEM) has been widely used for this purpose, while the technique never catches mechanical information of such materials in general. The realization of much-higher-performance materials requires the evaluation technique that enables us to investigate morphological and mechanical properties at the same time. AFM must be an appropriate candidate because it has almost comparable resolution with TEM. Furthermore, mechanical properties can be readily obtained by AFM due to the fact that the sharp probe tip attached to soft cantilever directly touches the surface of materials in question. Therefore, many of polymer researchers have started to use this novel technique." In this section, we introduce the results using the method described in Section 21.3.3 on CB-reinforced NR. 

The dynamic mechanical thermal analyzer (DMTA) is an important tool for studying the structure-property relationships in polymer nanocomposites. DMTA essentially probes the relaxations in polymers, thereby providing a method to understand the mechanical behavior and the molecular structure of these materials under various conditions of stress and temperature. The dynamics of polymer chain relaxation or molecular mobility of polymer main chains and side chains is one of the factors that determine the viscoelastic properties of polymeric macromolecules. The temperature dependence of molecular mobility is characterized by different transitions in which a certain mode of chain motion occurs. A reduction of the tan 8 peak height, a shift of the peak position to higher temperatures, an extra hump or peak in the tan 8 curve above the glass transition temperature (Tg), and a relatively high value of the storage modulus often are reported in support of the dispersion process of the layered silicate. 

S. Bourbigot and S. Duquesne, Intumescence and nanocomposites A novel route for flame-retarding polymeric materials, in Flame Retardant Polymer Nanocomposites, A.B. Morgan and C.A. Wilkie (Eds.), Wiley Interscience, Hoboken, NJ, 2007, pp. 131-162. 

Nanocomposites are already making an impact on the choice and use of polymeric materials. As the dimensions of the particles diminish into the range of a few nanometers, surface area effects dominate, changing fundamentally the interactions between particle and polymer. Often nanocomposites containing less than 5% additive have substantially improved properties with no adverse effects. 

Recent developments in the cross-polymerization of the organic components used in bicontinuous microemulsions ensure the successful formation of transparent nanostruc-tured materials. Current research into using polymerizable bicontinuous microemulsions as a one-pot process for producing functional membranes and inorganic/polymer nanocomposites is highlighted with examples. 

This bicontinuous-microemulsion polymerization method can also be used to synthesize polymer nanocomposites containing Si02 [101], Ti02, ZnO and many other semiconductors. The advantage of this method is that the nanoparticles of inorganic materials can be dispersed in the polymer matrix fairly uniformly. The only requirement is that nanomaterials should be first stabihzed... 

It is evident that the incorporation of POSS cages into polymeric materials often results in substantial improvements in polymer properties and offer the possibility to control the mechanical, chemical and physical properties of the system during polymerization as well. Intense efforts have recently been directed toward the development of new porous materials because of their utihty and potential utihty as catalysts and catalyst supports [208,209], dielectric materials for electronic appHcations [210], media for optical [211] and sensor [212] applications, and selectively permeabihty membranes [213] and precursors [10] for POSS nanocomposites. Significant property enhancements imparted by the inclusion of a nanosized inorganic... 

This volume is including information about thermal and thermooxidative degradation of polyolefine nanocomposites, modeling of catalytic complexes in the oxidation reactions, modeling the kinetics of moisture adsorption by natural and synthetic polymers, new trends, achievements and developments on the effects of beam radiation, structural behaviour of composite materials, comparative evaluation of antioxidants properties, synthesis, properties and application of polymeric composites and nanocomposites, photodegradation and light stabilization of polymers, wear resistant composite polymeric materials, some macrokinetic phenomena, transport phenomena in polymer matrix, liquid crystals, flammability of polymeric materials and new flame retardants. 

In this chapter, two new approaches for the synthesis of metal-polymer nanocomposite materials have been described. The first method allows the preparation of contact-free dispersions of passivated gold clusters in polystyrene, and it is based on a traditional technique for the colloidal gold synthesis—that is, the alcoholic reduction of tetrachloroauric acid in presence of poly(vinyl pyrrolidone) as polymeric stabilizer. The primary function of the stabilizer is to avoid cluster sintering, but it also allows us to isolate clusters by co-precipitation. It has been found that the obtained polymer-protected nanometric gold particles can be dissolved in alkane-thiol alcoholic solutions to yield thiol-derivatized gold clusters by thiol absorbtion on the metal surface. Differently from other approaches for thioaurite synthesis available in the literature, this method allows complete control over the passivated gold cluster structure since a number of thiol molecules can be equivalently used and the... 

Up to now we considered pol5meric fiiactals behavior in Euclidean spaces only (for the most often realized in practice case fractals structure formation can occur in fractal spaces as well (fractal lattices in case of computer simulation), that influences essentially on polymeric fractals dimension value. This problem represents not only purely theoretical interest, but gives important practical applications. So, in case of polymer composites it has been shown [45] that particles (aggregates of particles) of filler form bulk network, having fractal dimension, changing within the wide enough limits. In its turn, this network defines composite polymer matrix structure, characterized by its fractal dimension polymer material properties. And on the contrary, the absence in particulate-filled polymer nanocomposites of such network results in polymer matrix structure invariability at nanofiller contents variation and its fractal dimension remains constant and equal to this parameter for matrix polymer [46]. 

Georgy V. Kozlov, DSc, is a Senior Scientist at UNIID of Kabardino-Balkarian State University in Nal chik, Russian Federation. His scientific interests include the structural grounds of properties of polymeric materials of all classes and states physics of polymers, polymer solutions and melts, and composites and nanocomposites. He proposed to consider polymers as natural nanocomposites. He is the author of more than 1500 scientific publications, including 30 books, published in the Russia, Ukraine, Great Britain, Germany, Holland, and USA. 

Nowadays a promising way to control the bulk polymer properties, such as conductivity, processability, thermal, and mechanical stabihties, is through the organization of the polymeric chains on the nanometer scale [7-9]. The first approach used to achieve this goal was the synthesis of conducting polymers in cavities of porous hosts. Commonly named nanocomposites, these materials have two or more different components on the nanoscale, and can show catalytic, electronic, magnetic, and optical properties better than those of the individual phases. The basic reason for this synergism is still not fully understood, but it is considered that confinement and electrostatic interactions between the components play an important role. 

Stability of common polymers, and consequently, thermal degradation of mercaptide molecules ean be also carried out with the mercaptide dissolved into a polymeric medium. In this case, a finely dispersed inorganic solid phase, embedded in polymer, is generated. Materials based on clusters confined in polymeric matrices are called nanocomposites [Mayer, 1998 Caseri, 2000]. Both semiconductor-polymer and metal-polymer nanocomposites have unique functional properties that can be exploited for applications in several advanced technological fields (e.g., optics, nonlinear optics, magnetooptics, photonics, optoelectronics) [Caseri, 2000]. 

Sammut, R, Elongational flow of polymeric nanocomposites 4th International Symposium on Polymer Nanocomposites Science and Technology (PNC-2007), National Research Council Canada—Industrial Materials Institute, BouchervUle, Quebec, Canada, Oct. 18-19, 2007. 

---